The present invention relates to communications and particularly voice communications. More particularly, the present invention relates to a noise suppressing microphone apparatus for high clarity two way radio communications in high noise, and environmentally extreme conditions.
Two-way radio communications in high noise, environmentally extreme conditions is difficult, or often impossible. Such communications are often erratic, intermittent, and subject to various forms of environmental and operational interference and disruption. This is particularly true where high noise levels, moisture, and other challenging conditions of the particular applications environment are simultaneously effective. Such conditions are commonly found in military applications involving high-noise operations in the air such as helicopters and other types of aircraft, on the surface, such as tanks, air-cushion vehicles, and personnel carriers, and on or beneath the surface of a body of water, such as high speed boats, air-cushion watercraft, and submersibles.
Likewise, civilian applications include, but are not limited to, motorcycles, jet skis, skydiving, motor boating, firefighting, video games, voice input to computers, police work, voice recognition for computers, and hazardous materials applications. In most, if not all of such exemplary applications, hands-free operation is desirable, if not essential.
The environmental exposure to which such a microphone may be subjected includes high and low temperature, extraordinary shock and vibration effects during handling and use, high levels of audible sound interference, moisture, toxic, and chemically damaging agents. One of the best examples of an environment containing the broadest spectrum of challenging and extreme environmental factors is that of firefighting. The firefighting application demands the use of special apparel such as gloves, helmet liners, and face and eye protective elements that may contribute adversely to the use and operational effectiveness of prior art microphones.
Prior art conventional microphones are typically positioned on a boom in front of the user""s mouth to pick up speech. In this location, the microphone will pick up ambient background noise including wind and breathing noise, and other external noise. Also, microphones mounted on or within a helmet or mask worn by a user are prone to pick up not only the aforementioned sounds but resonation""s and reverberations of same. Such noise may completely drown out or obscure otherwise intelligible voice communications. Noise cancellation provided by special circuitry may be applied to the microphone output to achieve some degree of improvement. Such circuitry requires a power source and physical and functional support.
It is thus an object of the present invention to provide a microphone having noise suppression capability for use in a high-noise operationally challenging environment.
It is yet another object of the present invention to provide a solid state microphone having integrated mechanical noise filtration.
It is still another object of the present invention to provide a piezoelectric microphone having integrated mechanical noise filtration.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.
The present invention, the Noise Suppressing Microphone, is a piezoelectric sandwich transducer embedded in a mechanical noise filter, except for one transducer face employed for contact with the user""s body for pickup of user-created sound. The sandwich is a thin layer of piezoelectric film between two conductive thin film metallic layers to which output leads are attached. The sandwich is securely mounted to a flat, substantially inflexible substrate. This assembly is covered by a hydrophobic coating and then embedded in a single or multiple layer mechanical sound suppressing filter. The filter absorbs and dissipates ambient sound impinging on the filter material surrounding those portions of the transducer not in direct contact with the user""s body.
The microphone of the present invention is particularly effective when used in contact with the user""s forehead. However, using the invention to detect maximum sound pickup at various points on the user""s body will permit optimum location for a particular application.